Can I read in binary data with istream in c++?

Right now I am using istream to read in data. I have both text which I would like to read in as strings and numbers, and hashes which are read into character arrays. Since hashes are effectively random, I am hitting snags when I try to read it back in and hit EOF (which is part of the hash). Is there a way to accomplish this without resorting to fread. Also, is there a to use both istream and fread some I don't have to parse the integers and strings by hand. Finally, what is the best way to use fgets to get a string of unknown length.

Thanks, Eric

EDIT: Here is the code:

string dummy;
ifstream in(fileName);
for(int i=0; i<numVals; i++)
{
    int hashLen;
    in>>hashLen;
    char cc;
    in.get(cc);//Get the space in between
    cout<<"Got first byte: "<<(int)cc<<endl;

    char * hashChars = new char[hashLen];
    in.read(hashChars, hashLen);
    for(int j =0; j <hashLen; j++)
    {
        char c = hashChars[j];
       unsigned char cc = reinterpret_cast<unsigned char&>(c);
        cout<<"Got byte: "<<(int)c<<(int)cc<<endl;
        if(in.fail())
        {
            cout<<"Failed! "<<in.eof()<<" "<<in.bad()<<endl;
        }
    }

delete hashChars;

    getline(in,dummy);//get a dummy line
    cout<<"Dummy: "<<dummy<<" numvals: "<<numVals<<" i: "<<i<<" hashLength: "<<hashLen<<endl;
}

My output looks like:

1>Got first byte: 32

1>Got byte: 4 4

1>Got byte: -14 242

1>Got byte: 108 108

1>Got byte: 87 87

1>Got byte: 113 113

1>Got byte: -116 140

1>Got byte: -106 150

1>Got byte: -35 221

1>Got byte: 0 0

1>Got byte: -91 165

1>Got byte: 39 39

1>Got byte: 111 111

1>Got byte: 7 7

1>Got byte: 126 126

1>Got byte: 16 16

1>Got byte: -42 214

1>Dummy: numvals: 35 i: 12 hashLength: 16

1>Got first byte: 32

1>Got byte: 14 14

1>Failed! 1 0

1>Got byte: -65 191

1>Failed! 1 0

1>Got byte: -107 149

1>Failed! 1 0

1>Got byte: -44 212

1>Failed! 1 0

1>Got byte: -60 196

1>Failed! 1 0

1>Got byte: -51 205

1>Failed! 1 0

1>Got byte: -51 205

1>Failed! 1 0

Solution

When reading binary data you generally want to open your std::ifstream with the flag std::ios_base::binary. The resulting differences are fairly small but they generally do matter.

There are a few oddities in your code you might want to fix:

You always need to check after reading if the operation was successful, e.g., using if (in.read(hashChars, hashLen)) { ... }
There is no need to use reinterpret_cast<...>() which always has implementation defined semantics. You should use static_cast<unsigned char>(c) instead.
You allocate an array of characters but you release it using delete p. You need to use delete[] p instead. Using delete p results in undefined behavior. There isn't really any need to use new and delete at all, though, as std::vector<char> hashChars(hashLen) does automatic memory management.

There are a few [mutilated] questions otherwise embedded in the request above (so the questions/answers are guesses of what is being asked):

Can you mix std::istream::read() and fread() on the same stream (I suppose this is the question): not immediately unless the stream happens to be std::cin which reads from the same source as stdin. If you want to use both std::istream::read() and fread() on the same file you'll need to wrap a FILE* by a suitable std::streambuf and initialize an std::istream with the corresponding object.
How to read an arbitrary sized line with fgets()? You can't. The buffer to fgets() gets allocated before attempting to fill it and can always be filled before reaching a newline. You can use std::getline() to read an arbitrary long line, however. If you just want to skip the line, you can use in.ignore(std::numeric_limits<std::streamsize>::max(), '\n') when using std::istream. Off-hand I don't know if there is a similar operation for FILE*.